Cognitive decline reversed by cinacalcet.

An 85-year-old lady with decreased mood and low energy was found to have an elevated serum corrected calcium concentration of 2.8mmol/L (reference range: 2.1–2.6mmol/L). Plasma parathyroid hormone concentration was elevated at 390 pg/mL (reference range: 10–85 pg/mL). She had a past history of renal calculi. Renal function, full blood picture, erythrocyte sedimentation rate, 24-h urinary calcium excretion, serum immunoglobulins, chest X-ray and serum angiotensin converting enzyme concentrations were all normal. Myeloma screening was negative. Serum-corrected calcium concentrations fell following rehydration. A thiazide diuretic was discontinued. A sestamibi scan (Figure 1) was unhelpful in pre-operative localization. The patient declined parathyroidectomy. One year later, she was admitted with dehydration with serum-corrected calcium concentration elevated at 2.93mmol/L. This did not reduce in response to rehydration or diuretic therapy and had a minimal reduction with intravenous bisphosphonates. Mini Mental State Examination (MMSE) score was 21/30 and serum-corrected calcium was 2.85 nmol/L on discharge. Vitamin D concentration was low at 19 nmol/L (reference range: 50–100 nmol/L). She was not commenced on Vitamin D replacement. The following day, she presented with marked confusion, abdominal pain and decreased responsiveness. CT scan of brain showed no acute changes. ECG was normal, and there were no signs of systemic infection. MMSE was 6/30, and serum-corrected calcium concentration was 2.92mmol/L. Over the following 12 days, calcium did not reduce in response to repeated infusions of intravenous bisphosphonates. Her functional status had deteriorated and she was now fully dependent in all activities of daily living. Nursing home placement was being advanced by the family and social services. A trial of the calcimimetic agent cinacalcet was commenced at a dose of 30mg twice daily. Within 4 weeks, her serumcorrected calcium concentration was 2.15mmol/L, MMSE was 26/30 and mood and functional status had improved (Figure 2). This lady has now returned to independent living and remains on a maintenance dose of cinacalcet 30mg twice daily.